A Nationwide spokesman confirmed the society’s plan to convert around half of the 91 branches into Nationwide branches.
But added: “The remainder will either be closed or integrated into the nearest alternative Nationwide branch.”
The Nationwide acquired the brands at the height of the financial crisis when all three brands were experiencing financial difficulties.
The society said it believed the time was right to integrate the three mutuals into the stronger Nationwide brand.
Tony Prestedge, chief operating officer at Nationwide, said: “Having made considerable improvements to our range of products and services the only way we can ensure all our members benefit is to take this logical step to integrate our businesses under one unified, strong and nationally recognisable brand.
“The strength of the Nationwide brand is increasingly compelling and we will now be able to offer customers of the Cheshire, Derbyshire and Dunfermline a vastly improved proposition.
“As well as benefiting from access to our full suite of products and market leading customer service, more people will have access to our strong branch network with around 15% more customers of our regional brands being within 5 miles of a Nationwide branch than at present.
“The integration of the branches of the Cheshire, Derbyshire and Dunfermline into the Nationwide brand will result in significant efficiencies for the business ensuring that Nationwide is even better placed to cement its position as the real alternative to the high street banks.”
The integration marks the end of an era for three of the UK’s established mutual brands. The Derbyshire was established in 1859 and was the 9th largest building prior to the merger with Nationwide.
The Dunfermline was established in 1869 and was Scotland’s largest building society before the merger. The Cheshire was established in 1870 and was the 11th largest in the United Kingdom before the takeover.
The Nationwide initially announced plans to integrate the brands in 2012.
